Concrete building construction with improved post tensioning means

ABSTRACT

A building assembly having aligned first panels and a second panel between each pair of adjacent first panels with the first panels having aligned, rod-receiving conduits and the second panels having sleeves aligned with the conduits so that reinforcing rods can extend through the assembly of the first and second panels. Each sleeve has means for guiding reinforcing rods therethrough and a nut is received within the guide means for interconnecting the proximal ends of a pair of adjacent reinforcing rods. Each conduit is wide enough to receive a rodconnecting nut and the string of reinforcing rods are tensioned at the upper end of the building assembly, whereby uniform stress is applied to the first and second panels and thereby to the overall building assembly.

United States Patent [1 1 Minutoli et al.

[22] Filed: Mar. 23, I972 [21] Appl. No.: 237,420

[52] US. ,Cl 52/125, 52/227, 52/240,

52/251, 52/298, 52/585 [51] Int. Cl. E04b 1/41, E04g 21/12 [58] Field of Search 52/125, 240, 258,

[56] References Cited UNITED STATES PATENTS 3,226,894 1/1966 Burchardt et al 52/227 X 3,621,626 11/1971 Tylius 52/227 3,691,708 9/1972 Firnkas 52/251 X 3,156,169 11/1964 Finsterwalder 52/228 X 3,566,560 3/1971 Wakefield et al.. 52/251 X 3,662,506 5/1972 Dillon 52/251 3,500,595 3/1970 Bennett 52/228 X 2,929,236 3/1960 Stewart et a1 52/228 1 Jan. 1, 1974 3,382,632 5/1968 Grofcsik 52/228 1,385,606 7/1921 Christensen 52/240 X FOREIGN PATENTS OR APPLICATIONS 102,933 1/1966 Denmark 52/125 435.675 10/1967 Switzerland 52/250 Primary ExaminerFrank L. Abbott Assistant Examiner-Leslie A. Braun Attorney-Stephen S. Townsend et al.

[5 7 ABSTRACT A building assembly having aligned first panels and a second panel between each pair of adjacent first panels with the first panels having aligned, rod-receiving conduits and the second panels having sleeves aligned with the conduits so that reinforcing rods can extend through the assembly of the first and second panels. Each sleeve has means for guiding reinforcing rods therethrough and a nut is received within the guide means for interconnecting the proximal ends of a pair of adjacent reinforcing rods. Each conduit is wide enough to receive a rod-connecting nut and the string of reinforcing rods are tensioned at the upper end of the building assembly, whereby uniform stress is applied to the first and second panels and thereby to the overall building assembly.

11 Claims, 4 Drawing Figures PATENTEU JAN 1 4 M. A 4 i N mIWIIAJ all/4' HM H... "H

mm F //-32 4o 30 34 I l// 1 CONCRETE BUILDING CONSTRUCTION WITH IMPROVED POST TENSIONING MEANS This invention relates to improvements in the prestressing of walls and floors of a building and, more particularly, to an improved concrete building assembly having improved prestressing means therefor.

In erecting a concrete building, the floor and wall panels are often prestressed one story at a time by the application of prestressing forces to the reinforcing rods which extend vertically through the walls and floor panels. While this technique is satisfactory in some cases, it is more advantageous to stress uniformly the entire side walls and floor panels in a building. Thus, the separate prestressing of each story results in delays and the expenditure of much effort which could be used more effectively elsewhere in erecting a building.

The present inventiosn is directed to an improved concrete building construction which allows a multistoried bulding to be uniformly prestressed throughout in a simple manner, while avoiding the delays occasioned by the need to prestress the reinforcing rods corresponding to a single story of a building. In addition, the invention is directed to a novel system for leveling and aligning the compoents of a multi-story building during erection.

To this end, the building construction of the invention includes aligned spaced, first concrete panels and a second concrete panel between an adjacent pair of first panels with panels having improved rod-receiving means therethrough permitting a string of reinforcing I rods to be shiftably mounted therein and to readily extend therethrough so that, when the building is fully erected, the rod string can be tensioned in a one-step operation from the top of the building to cause the first and second panels adjacent to the rod string to be uniformly prestressed. This technique avoids the need to conventionally post-tension, by means of a hydraulic ram or jack, a rod string at each story of a building. This minimizes the time and effort required to prestress the various panels forming the stories of a multi-storied building inasmuch as only a single step accomplishes both post-tensioning and interlocking assembly of the entire structure. Therefore, the prestressing procedure is not only to achieve a stressed end product, but also to force alignment The invention object of this invention is, therefore, to provide an improved concrete building building wherein the construction includes improved rod tensioning means for reinforcing rods shiftably extending through the various floor and wall panels of a building so as to permit uniform prestressing of such panels of the building at the top of the latter, and after the panels components been completely erected to minimize the time and effort required for this purpose. A further advantage is the ease with which periodic tests of rod stress can be conducted, during the life of the building. Contemplated within the scope of this invention is, alternatively, the lateral prestressing of a plurality of floor panels.

Another object of this invention is to provide a building construction of the type described wherein each panel has conduit means therethrough for receiving a reinforcing rod with the conduit means being sufficiently large to permit a pair of adjacent reinforcing rods to be releasably interconnected and to move at least partially therethrough when the rod string is tensioned so that there will be no interference from the adjacent panels while assuring that the panels will be uniformly prestressed.

A further object of this invention is to provide a building construction of the type described wherein the building can be readily assembled and disassembled, floors added or removed, and damaged panels readily replaced.

Still another object of this invention is to provide a building construction capable of either floor by floor stressing and/or overall stressing of pre-stressed rods (or multi-strand cables).

Other objects of this invention will become apparent as the following specification progresses, reference being had to the accompanying drawing for an illustration of the invention.

IN THE DRAWINGS FIG. 1 is an exploded, perspective view of the building construction of this invention;

FIG. 2 is an enlarged, fragmentary cross-sectional view of the building construction with the side wall and floor panels in operative positions with respect to each other;

FIG. 3 is a fragmentary, perspective view of the upper end of one of the side wall panels; and

FIG. 4 is a cross-sectional view taken along 4-4 of FIG. 3.

The building wall construction of this invention is broadly denoted by the numeral 10 and includes a plurality of first concrete panels, two of which are shown in FIGS. 1 and 2, the two panels being denoted by the numerals I2 and 14. These two panels can either form vertical walls or could, within the purview of the invention, form horizontal walls or floor members. Furthermore, it will be appreciated by one skilled in this art that panels 12 and 14 can also be beams, columns, and other structural elements less than or more than a panel. In addition, panels 12 and 14 may be formed of metal, plastic or various other conventional building materials.

For purposes of illustration only, panels 12 and 14 will be described as defining vertical side walls, wall 14 being above and aligned with wall 12. Between each pair of the first panels is a second concrete panel 16. For purposes of illustration only, panel 16 defines a floor member between and abutting the proximal end faces 18 and 20 of panels 12 and 14. Panel 16 is essentially perpendicular to panels 12 and 14 as shown in FIG. 2, panels 12, 14 and 16 being rectangular and of a predeten'nined thickness, it being understood that the thickness of panel 16 may be different from that of the other panels. Thus, construction 10 will be comprised of a plurality of aligned first panels and a number of second panels to form a particular type of building such as a multi-storied building, assuming that the various panel 16 define floor members while the various first panels, such as panels 12 and 14, define side walls spanning a distance between adjacent pairs of floor members.

Each of the first concrete panels, for instance, panel 12, is provided with a conduit or rod receiving passage 22 therethrough between the opposed end faces thereof. As shown in FIG. 1, passage 22 of panel 12 extends downwardly from upper flat end face 18 and terminates at the lower flat end face (not shown) thereof. Each passage 22 has open ends, whereby a reinforcing rod can be fed through the passage.

The upper and lower flat end faces of each first concrete panel is provided with respective anchor plates 24 and 26, FIG. 1 showing upper anchor plate 24 of panel 12 and lower anchor plate 26 of panel 14. Each anchor plate is embedded in the corresponding end face and has an outer surface flush with the outer surface of the end face. Also, each anchor plate includes a pair of L shaped anchors which are also embedded in the respective panels as shown in FIG. 2 to prevent removal of the anchor plate therefrom. It will be apparent to those skilled in this art that there could be any number of L shaped anchors and that the particular shape thereof can vary widely.

Each upper anchor plate 24 can be provided with a keyhole shaped slot 30 therein so as to form concrete insert lifting assembly-31. Slot 30 is shaped to receive the lower end of a lifting rod (or cable) 32 in the manner shown in FIGS. 3 and 4. Rod 32 is provided with a ball or bead 34 on its lower end, the ball being received within the enlarged portion 36 of slot 30, then moved laterally into the smaller portion 38 of slot 30 to hook under the lower surface of plate 24, thereby permitting the panel to be elevated as rod 32 is raised. A second anchor plate 24 can be mounted in the upper face 18 of each first concrete panel to receive a second lifting rod to facilitate the lifting of the panel.

The enlarged portion 36 of each slot 30 is aligned with the upper end of the corresponding passage. The outer end of enlarged portion 36 has a beveled surface 40 to provide a seat for a bushing in a manner to be described. Also, the lower, outer end of each anchor plate 26 is provided with a beveled annular surface as shown in FIG. 2. Surface 40 can be formed beveled (tapered) as shown or as the female portion of a conventional ball and socket.

Each second panel 16 is provided with an internally threaded sleeve 42 having open ends substantially flush with the opposed flat faces 44 and 46 thereof. Also, each sleeve 42 is enlarged at its central region as shown in FIG. 2 to effect anchoring of the sleeve in the panel. Alternatively, sleeve 42 can be provided with laterally positioned segments of reinforcing rod extending radially outward from sleeve 42 even so far as to be in attachment with other sleeve members embedded in the panel.

A first, externally threaded bushing 48 is threaded into one end of sleeve 42 and a second externally threaded bushing 50 is threaded into the opposite end of the sleeve. Where independent adjustment of the bushings relative to sleeve 42 is not essential, bushings 48 and 50 can be formed as an integral unit with sleeve 42. Each of these two bushings have beveled annular outer end faces for complementarily engaging the adjacent annular surfaces of respective anchor plates 24 and 26. Thus, the seats defined by the beveled surfaces of anchor plates 24 and 26 serve to guide each pair of first panels into proper positional relationship to the corresponding second panel therebetween. Also, bushings 48 and 50 define guides for guiding a reinforcing rod from one first panel, through the adjacent second panel and into the next adjacent first panel.

A string of reinforcing rods are placed in the aligned passages 22 and sleeves 42 as building construction is erected. Initially, the lowermost reinforcing rod 52 is coupled to an anchor (not shown) in the building foundation in a fixed position to the lowermost first con crete panel, such as by a nut 54 (FIG. 2). Thereafter,

the various reinforcing rods are interconnected by internally threaded nuts 56, only one of which is shown in FIGS. 1 and 2. The term reinforcing rod" is intended to define prestressed rod or multi-strand cable, having an ultimate strength in excess of 20.000 pounds/square inch. Although rods 52 and 59 are illustrated as having a length corresponding to the width of a panel, it is contemplated that rods having a length corresponding to 2 or more panels can also be utilized. Furthennore, the rods can be installed subsequent to the initial erection of the floor and wall panels.

Nuts 56 are initially received within countersunk regions 58 of respective bushings 48, in the manner shown in FIG. 2. Moreover, the opening through each anchor plate 24 or 26 is large enough to pass nuts 56; in addition, the inner transverse dimension of each passage 22 is large enough to allow a nut 56 to move thereinto, such as when the rod string istensioned so as to cause some elevation of the rod string itself. As shown in FIGS. 1 and 2, a second reinforcing rod 59 is coupled to rod 52 by nut 56 and the upper end of the rod string is provided with a nut 60, threadably mounted on the uppermost end of the upper reinforcing rod.

In use, the various first and second panels are stacked in a manner to erect construction 10, whereupon the reinforcing rods are progressively put into place. It is understood that the reinforcing rods can be placed in respective passages 22 and sleeves 42 at various locations in construction 10, FIGS. 1 and 2 showing only a single operative location for a string of reinforcing rods. In each case, the reinforcing rods extends through the first panels and second panels and, when the rods are to be interconnected, they are coupled together by nuts 56 as shown in FIG. 2. After construction 10 is fully erected, nuts 60 are put into place and tightened to tension the respective rod strings so that a uniform prestessing of the various first and second panels is achieved. In this way, the various panels corresponding to a particular story of building construction 10 need not be individually tensioned or prestressed but the entire construction can be prestressed after all of the first and second panels are put into place. Thus, considerable time and effort is avoided to thereby increase the efficiency of erecting construction 10. As each rod string is tensioned, the string may elevate and nut 56 may enter the passage 22 thereabove. The passage is sufficiently large to allow a nut 56 to enter the same so as to avoid the binding of the nut on the adjacent panel. In some cases, it will be desirable to pressure grout the void space within conduit 22 around the reinforcing rod. In addition, it will be apparent to those skilled in this art that various forms of compressible or noncompressible grouting may be employed between abutting portions of the panels. In some cases, where metal brackets are employed, the reinforcing rods (or cables) may be eliminated and the metal portions welded together.

In the claims: y

1. In a building construction: a plurality of first, spaced, aligned concrete panels; a second concrete panel for each pair of adjacent first panels, respectively, each second panel being between the respective pair of first panels and projecting transversely thereof; each first panel having a rod-receiving conduit therethrough, the conduits of the first panels being aligned with each other, each said first panel having anchor plates secured thereto and overlying said conduits,

each of said anchor plates having an outwardly beveled opening in surrounding relationship to said conduit to provide a seat; each second panel having a sleeve for alignment with the corresponding conduits of respective first panels, whereby reinforcing rod means can extend through the conduits and the sleeves of said panels; and guide means releasably coupled to each end of said sleeve, respectively, for alignment of each said second panel with said corresponding pair of said first panels, each of said sleeves including a tapered outer end engageable with the seat of the adjacent anchor plate, the inner transverse dimension on each conduit being sufficient to permit a fastener interconnecting a pair of adjacent reinforcing rods of said rod means to move into and at least partially through the conduit.

2. in a building construction as set forth in claim 1, wherein said guide means includes a bushing threadably mounted in the sleeve and provided with a countersunk region at one end thereof for receiving said fastener.

3. in a building construction as set forth in claim 1, wherein the sleeve is internally threaded, said guide means including an externally threaded bushing for each end of the sleeve respectively, one of the sleeves having a countersunk region at its normally outermost end for receiving a said fastener, each bushing having a tapered outer end, each first panel having a pair of generally flat, opposed end faces in juxtaposition to the adjacent second panels with each of said end faces having a beveled outer surface complemental to the tapered end of the adjacent bushing.

4. in a building construction as set forth in claim 1, wherein each first panel has a pair of opposed end faces, there being an anchor plate embedded in each of said end faces of each first panel, respectively, one of the end plates having a keyhole-shaped slot therein for receiving one end of a lifting rod with the lifting rod having a lateral projection thereon receivable within the slot below the narrowest portion thereof.

5. In a building construction as set forth in claim 1, wherein the first panels are vertically aligned and each second panel extends in a generally horizontal plane transversely to the adjacent first panels, and wherein is included a rod string including a number of reinforcing rods for placement in the aligned conduits and sleeves, and a fastener for interconnecting the proximal ends of a pair of adjacent reinforcing rods, and means on the upper end of the rod string for tensioning the same to thereby prestress the corresponding panels.

6. In a building construction as set forth in claim 5, wherein said fastener includes an internally threaded nut for threaded attachment to said pair of rods.

7. In a building construction as set forth in claim 1, wherein each sleeve has an enlarged central region to effect the anchoring of the sleeve in the corresponding second panel.

8. In a building construction as set forth in claim 1, wherein said plurality of first panels constitute floor panels.

9. In a building construction: a plurality of vertically aligned, spaced concrete side walls, each side wall having a vertical conduit therethrough and a pair of opposed upper and lower end faces, there being an anchor plate embedded in each of said end faces, respec-.

tively, with each anchor plate having a hole therethrough aligned with the corresponding conduit, the outer face of each anchor plate being substantially flush with the adjacent end face and provided with a beveled outer surface concentric to the corresponding conduit; a concrete floor member for each pair of adjacent side walls, repsectively, each floor member having an internally threaded sleeve embedded therein with each sleeve having a pair of opposed upper ends at the upper and lower surfaces of the floor member; a pair of externally threaded bushings threadably mounted in the sleeve adjacent to the opposed ends thereof, each bushing having a tapered outer end surface complemental to the beveled outer surface of the adjacent anchor plate, the upper bushing of each floor member having a countersunk region; a rod string including at least a pair of reinforcing rods extending through the conduits and the sleeves; a nut receivable in the countersunk region of said bushing of a floor member for releasably interconnecting the proximal ends of the adjacent reinforcing rods, the inner transverse dimension of each conduit being sufficient to permit the nut to travel therethrough; and means coupled with the uppermost rod of said rod string for applying tension thereto to thereby prestress the side walls and the floor members.

10. in a building construction of the type having a plurality of aligned, spaced concrete first panels and a second concrete panel between each pair of first panels, respectively, with each first panel having a pair of opposed end faces and each second panel having a pair of opposed side faces, the improvement comprising: a panel prestressing structure including means adapted to provide a rod-receiving conduit for each first panel, respectively, with each conduit extending substantially between said end faces of the corresponding first panels, an anchor plate adapted to be embedded in each end face, respectively, of each first panel with the outer surface of each anchor plate being substantially flush with the corresponding end face, each anchor plate having a rod-receiving hole therethrough for alignment with the adjacent conduit and a beveled outer surface concentric with the hole, an internally threaded sleeve for each second panel, respectively, each sleeve adapted to be embedded in the respective second panel in spanning relationship to the side faces thereof, an externally threaded bushing for each end of each sleeve, respectively, each bushing having a tapered outer end for complementally engaging the beveled outer surface of the adjacent anchor plate, one of the bushings having a countersunk region at its outer end, a rod fastener receivable within said region, a rod string including at least a pair of reinforcing rods, said fastener being adapted to releasably interconnect said pair of rods to form said rod string, and means carried on the outer end of one of the rods for tensioning the same as the rod string extends through the conduits and the sleeves and when said first and second panels are in operative positions with respect to each other.

11. In a building construction of the type having a plurality of aligned, spaced concrete first panels and a second concrete panel between each pair of first panels, respectively, with each first panel having a pair of opposed end faces and each second panel having a pair of opposed side faces, the improvement comprising: an anchor plate embedded in each of said end faces, respectively, the outer face of each anchor plate being substantially flush with the adjacent end face and provided with an inwardly beveled outer surface portion, each second panel having an internally threaded sleeve embedded therein in spanning relation to the side faces 7 8 thereof, with each sleeve having a pair of opposed outer end surface complemental to the beveled outer outer ends at the upper and lower side faces of said sec- Surface portion of the adjacent anchor plate for aligm nd panel; and a pair of externally threaded bushings threadably mounted in the sleeve adjacent to the op posed ends thereof, each bushing having a tapered ing said first panel with said second panel. 

1. In a building construction: a plurality of first, spaced, aligned concrete panels; a second concrete panel for each pair of adjacent first panels, respectively, each second panel being between the respective pair of first panels and projecting transversely thereof; each first panel having a rod-receiving conduit therethrough, the conduits of the first panels being aligned with each other, each said first panel having anchor plates secured thereto and overlying said conduits, each of said anchor plates having an outwardly beveled opening in surrounding relationship to said conduit to provide a seat; each second panel having a sleeve for alignment with the corresponding conduits of respective first panels, whereby reinforcing rod means can extend through the conduits and the sleeves of said panels; and guide means releasably coupled to each end of said sleeve, respectively, for alignment of each said second panel with said corresponding pair of said First panels, each of said sleeves including a tapered outer end engageable with the seat of the adjacent anchor plate, the inner transverse dimension of each conduit being sufficient to permit a fastener interconnecting a pair of adjacent reinforcing rods of said rod means to move into and at least partially through the conduit.
 2. In a building construction as set forth in claim 1, wherein said guide means includes a bushing threadably mounted in the sleeve and provided with a countersunk region at one end thereof for receiving said fastener.
 3. In a building construction as set forth in claim 1, wherein the sleeve is internally threaded, said guide means including an externally threaded bushing for each end of the sleeve respectively, one of the sleeves having a countersunk region at its normally outermost end for receiving a said fastener, each bushing having a tapered outer end, each first panel having a pair of generally flat, opposed end faces in juxtaposition to the adjacent second panels with each of said end faces having a beveled outer surface complemental to the tapered end of the adjacent bushing.
 4. In a building construction as set forth in claim 1, wherein each first panel has a pair of opposed end faces, there being an anchor plate embedded in each of said end faces of each first panel, respectively, one of the end plates having a keyhole-shaped slot therein for receiving one end of a lifting rod with the lifting rod having a lateral projection thereon receivable within the slot below the narrowest portion thereof.
 5. In a building construction as set forth in claim 1, wherein the first panels are vertically aligned and each second panel extends in a generally horizontal plane transversely to the adjacent first panels, and wherein is included a rod string including a number of reinforcing rods for placement in the aligned conduits and sleeves, and a fastener for interconnecting the proximal ends of a pair of adjacent reinforcing rods, and means on the upper end of the rod string for tensioning the same to thereby prestress the corresponding panels.
 6. In a building construction as set forth in claim 5, wherein said fastener includes an internally threaded nut for threaded attachment to said pair of rods.
 7. In a building construction as set forth in claim 1, wherein each sleeve has an enlarged central region to effect the anchoring of the sleeve in the corresponding second panel.
 8. In a building construction as set forth in claim 1, wherein said plurality of first panels constitute floor panels.
 9. In a building construction: a plurality of vertically aligned, spaced concrete side walls, each side wall having a vertical conduit therethrough and a pair of opposed upper and lower end faces, there being an anchor plate embedded in each of said end faces, respectively, with each anchor plate having a hole therethrough aligned with the corresponding conduit, the outer face of each anchor plate being substantially flush with the adjacent end face and provided with a beveled outer surface concentric to the corresponding conduit; a concrete floor member for each pair of adjacent side walls, respectively, each floor member having an internally threaded sleeve embedded therein with each sleeve having a pair of opposed upper ends at the upper and lower surfaces of the floor member; a pair of externally threaded bushings threadably mounted in the sleeve adjacent to the opposed ends thereof, each bushing having a tapered outer end surface complemental to the beveled outer surface of the adjacent anchor plate, the upper bushing of each floor member having a countersunk region; a rod string including at least a pair of reinforcing rods extending through the conduits and the sleeves; a nut receivable in the countersunk region of said bushing of a floor member for releasably interconnecting the proximal ends of the adjacent reinforcing rods, the inner transverse dimension of each conduit being sufficient to permit the nut to travel therethrougH; and means coupled with the uppermost rod of said rod string for applying tension thereto to thereby prestress the side walls and the floor members.
 10. In a building construction of the type having a plurality of aligned, spaced concrete first panels and a second concrete panel between each pair of first panels, respectively, with each first panel having a pair of opposed end faces and each second panel having a pair of opposed side faces, the improvement comprising: a panel prestressing structure including means adapted to provide a rod-receiving conduit for each first panel, respectively, with each conduit extending substantially between said end faces of the corresponding first panels, an anchor plate adapted to be embedded in each end face, respectively, of each first panel with the outer surface of each anchor plate being substantially flush with the corresponding end face, each anchor plate having a rod-receiving hole therethrough for alignment with the adjacent conduit and a beveled outer surface concentric with the hole, an internally threaded sleeve for each second panel, respectively, each sleeve adapted to be embedded in the respective second panel in spanning relationship to the side faces thereof, an externally threaded bushing for each end of each sleeve, respectively, each bushing having a tapered outer end for complementally engaging the beveled outer surface of the adjacent anchor plate, one of the bushings having a countersunk region at its outer end, a rod fastener receivable within said region, a rod string including at least a pair of reinforcing rods, said fastener being adapted to releasably interconnect said pair of rods to form said rod string, and means carried on the outer end of one of the rods for tensioning the same as the rod string extends through the conduits and the sleeves and when said first and second panels are in operative positions with respect to each other.
 11. In a building construction of the type having a plurality of aligned, spaced concrete first panels and a second concrete panel between each pair of first panels, respectively, with each first panel having a pair of opposed end faces and each second panel having a pair of opposed side faces, the improvement comprising: an anchor plate embedded in each of said end faces, respectively, the outer face of each anchor plate being substantially flush with the adjacent end face and provided with an inwardly beveled outer surface portion, each second panel having an internally threaded sleeve embedded therein in spanning relation to the side faces thereof, with each sleeve having a pair of opposed outer ends at the upper and lower side faces of said second panel; and a pair of externally threaded bushings threadably mounted in the sleeve adjacent to the opposed ends thereof, each bushing having a tapered outer end surface complemental to the beveled outer surface portion of the adjacent anchor plate, for aligning said first panel with said second panel. 